A multiscale investigation based on variance analysis for hand lay-up composite manufacturing

The large majority of polymeric composites are manufactured by hand lay-up, mainly due to its flexibility. However, the mechanical properties are directly influenced by the stacking sequence, fiber volume fraction and morphology, as well as the cure process. This study takes into consideration an E-glass/epoxy plain weave woven fabric composite made by hand lay-up. After the staking sequence is completed, three sets of plates are selected and each one is cured differently. The three selected cure processes are: cure on air, cure vacuum assisted, and cure under compression. A variance study based on stiffness and strength from ASTM D 3039/3039M tensile tests is performed to check the statistical differences caused by the cure processes. Additionally, a microscopic analysis was performed to identify the voids formation rate. The coupling between macro and micro-mechanical analysis is done by a non-dimensional coefficient which is able to capture the rate of defects generated by each cure process.